Realism Overhaul Discussion Thread

[Hattivat]

Guys what are the best mods for a person that want to make perfect replica and basically nothing of more?

Depends how "perfect" you want it to be. FASA is great for pre-1970 American stuff, but is not a "perfect" replica. For Russian stuff, Raidernick is the current king with beautiful probes and manned spacecraft on offer. For modern engines the best models we have are bobcat's. There is also LazTek for SpaceX replicas, and Lionhead for ESA. There are additionally other mods for the ISS, the Space Shuttle, Proton, Skylab, etc., just check the "supported mods" section in the Realism Overhaul main thread.

[Daze]

Depends how "perfect" you want it to be. FASA is great for pre-1970 American stuff, but is not a "perfect" replica. For Russian stuff, Raidernick is the current king with beautiful probes and manned spacecraft on offer. For modern engines the best models we have are bobcat's. There is also LazTek for SpaceX replicas, and Lionhead for ESA. There are additionally other mods for the ISS, the Space Shuttle, Proton, Skylab, etc., just check the "supported mods" section in the Realism Overhaul main thread.

Thanks

[MysteriousSteve]

I'm getting NullRefs when I try to load a craft, has anyone seen this before?

[NathanKell]

Yes, about once every four pages.

Oh, you mean "have we seen [your problem]" rather than "have we seen someone say, effectively "help mod doesn't work, fix pls?"

Please actually provide some details, and then we'll be able to help. Please check out this How To Get Support (Read First) thread for the sort of additional info we need to be able to help.

[Motokid600]

I have some questions about orbital rendezvous. How exactly are they done in real life? Was "Launch to rendezvous." ever actually performed? And where exactly can i learn on how to make low energy rendezvous? Because last night i was unable to rendezvous with the Agena in the FASA Gemini. The real life one has no engine on that upper stage, just a weak RCS thruster. This thruster is far to weak to make a "Lauch to orbit" because the relative speed is far to high for the weak engines. So before i give up and use the fake stage with the engine... how was it done?

[NathanKell]

Motokid600: check the last entry here.

[Motokid600]

Forgot about that comment. Thanks Nathan that was a good read. Got another question. Go figure! The Saturb 1B. Now ive seen people posting about troubles with this craft in the past. I dont know if it was stock or RSS, but it seems the 1B is a tricky beast. I cannot get the required Dv out of it. Not even close. I can cheat, throw some SRBs on the 1B and a second J2 and that'd do it. But before i give into that id really like to try and make the craft work as it was. How they did it.. no idea. I have stripped the Apollo capsule and service module of 95% of all propellents and cut the ablative sheiding by three quarters. And again I dont even get close.

It seems the S1B cuts off too early with only 2,712m/s of Dv. The single J2 engine of the S-IVB has a good number at 4,511 Dv, but nowhere near the thurst to take over the rest of the flight and I end up fighting gravith with a 40 degree pitch the entire time. The S-IVB could do it, but the S1B is not boosting it far enough. I have enough fuel then in the service module for 768 m/s. But then i go and read the S-IVB did the job without the use of the service engine to complete the orbit. It was at that point i decided i needed to inquire about this. Every flight my trajectory just got steeper and steeper and everytime I came up drastically short. I try to cicularize after Ap before i hit the atmosphere, no luck. And yet through all this I am actually cheating a bit by using the most powerful of each engine variant. The H1/RS-27 and the J2-S provide me with the most Dv. So at what point should I consider this a bug vs player error?

Edit: I dont know if its related, but I had to use a procedural decoupler for the dual plane seperation. The only one i have is the 5m part for the SaturnV and cant be sized. Cant find one for the S1B diamter so the procedural part worked nice. And its 2.25 tons versus 0.43 on the larger 5m part. Well crap im guessing theres my culprit.

Edit 2: Doesnt make much of a difference without it. 2,881 Dv on the S1 without the dual plane seperation, but it'd be nice to loose the ulage motors as It should be done for the S-IVB. The APS doesnt have the kick for the J2 to ignite and i dont have the time to wait for the fuel to settle before i have to get on the throttle. Thing flies... and falls like a brick.

Edit: 3: The more i look into this the more it seems my issue is the S-IVB. My numbers for the S1B are quite close to the real ones. And now that i think about i remember looking at the fuel after the S-IVB cuttoff. There was a good bit of liquid hydrogen left over. So i tried removing the fuels then replacing them. And the Dv went up too 2,888. ( im guessing because im using the J2S ). And still i dont think it is enough.

Edited March 18, 2015 by Motokid600

[NathanKell]

Maybe FASA changed (again), I'll check it out.

[ferram4]

Motokid, you are only trying to orbit the payload that the Saturn IB is rated for, right? It's only designed to put 18.6t of payload into orbit, and with that it certainly has enough dV to make it up there, ~9.9 km/s. Make sure that you're not carrying any extra dead weight. The S-IVb should be 118.8t, with 12.9t of that being dry mass (counting the APS and ullage motors, which were on all of them). Are you making sure that you're launching with a full fuel load and that none has boiled off due to timewarping to a launch window or due to KCT?

[Motokid600]

Motokid, you are only trying to orbit the payload that the Saturn IB is rated for, right? It's only designed to put 18.6t of payload into orbit, and with that it certainly has enough dV to make it up there, ~9.9 km/s. Make sure that you're not carrying any extra dead weight. The S-IVb should be 118.8t, with 12.9t of that being dry mass (counting the APS and ullage motors, which were on all of them). Are you making sure that you're launching with a full fuel load and that none has boiled off due to timewarping to a launch window or due to KCT?

I will double check my weights asap Ferram. I'd like to think I'm under 18.6tons. Any more propellant removed and the service module will be a dummy block. Ive got it down to 1/16th of a tank for fuel and rcs. Removed all fuel cells and even halved the lithium hydroxide. Removed most of the ablative shielding and cut out half the solid fuel out of the escape tower. Oh AND took half the fuel out of the APS. Yea I'm launching right off the bat. No time warp.

So... There might very well be some dry mass issues going on here or something. I'll report back soon as I can.

Edited March 18, 2015 by Motokid600

[NathanKell]

Total mass of the LV plus payload should be ~590t. Make sure all your H-1 engines are in H-1B config, and your J-2 is in J-2 config. Remove and re-add the fuel from the S-IB tank and the S-IVB tank.

[Motokid600]

I decided to rebuild the rocket from the LM adapter down using the right engine configs as Nathan said. And by removing the fuel from the tanks before placing the engines and then adding it back in gave me better results.

The CSM package is 10.1t with just 185 m/s of Dv.

The S-IVB is 146.4t and gives me 6,360 Dv. 136 without the CSM. 22t dry. ( 0.62 TWR ) According to Ferram's 118.8t/12.9t dry. Thats heavy. My little adapter piece is only 2.

The S1B as a whole is 592.6 and gives me 3,043-3,438 atm/vac Dv. ( 1.25 SLT TWR )

The extra few tons i imagine is from said improvised decoupler for the CSM-LM adapter. Having trouble with the FASA part. It seems the nodes are not quite in the right posistion and the adapter doesnt come up far enough leaving a gap between it and the service engine. So i placed a procedural interstage between the two and attatched that to the bottom of the service engine. Which allowed me to raise and lower the adapter as i pleased. It works, but it does add that extra weight because you need to use fairings on the proc IS adapter so it holds.

Theres that and not having a decoupler the correct size of the S1B for the dual plane seperation. The procedural one worked good, but was too heavy. So ive since been hot staging to save weight on ullage and crossing my fingers the insterstage does clip off the J2. Lol. Its been quite the learning experience thus far and im enjoying it none the less. I was unable to reach orbit with that configuration, but now i think it comes down to the pilot. Far as im concerned those Dv numbers are enough so its something im doing...

Im flying a steeper trajectory then any other rocket with the S1B. 750m start, 165km end, 15 degree final angle, 70 degree pitch angle. .. Really steep flight for the S1B. Too steep? Cant imagine any less. 1,400 m/s vertical speed after staging and a 235-250km Ap. I still cant hit the needed velocity before the S-IVB is back in the atmosphere.

Edited March 19, 2015 by Motokid600

[NathanKell]

Something is very fishy here. Under your CSM try a procedural interstage, set to 6.6m diameter, and four fairing panels. Under that add the "S-IVB stage" part. Under that add a J-2 engine. Then get the "S-IVB interstage for S-IB" part and place that. Then place the "S-IB stage" and add two sets of four H-1Bs to the bottom. Finally add 8x fins, and 2x Saturn APS to the S-IVB stage. That's all you should have.

[Motokid600]

Two APS modules? Been using four. So that couldnt have helped much. Also... The instrument unit as well?

As for that adapter. I had originally done what you said Nathan and made my own 6.6m adapter. Don't know if maybe its a procedural fairings issue, but it's heavy. Too heavy. The base and four fairings come up to almost four tons if I recall correctly. I'll double check that asap. But I know for a fact is was heavy enough for me to have to find an alternative. Which was using the correct, much lighter FASA adapter with my own very little interstage adapter in between where the LEM would go to be able to raise and lower the CSM to the right height. And in the end it was significantly lighter. Everything else is as you said. What's strange here is... All that doesn't equate to the amount of extra weight I have on the S-IVB.

But despite that I think it can be done. What's the margin of error for the S1B flight path? Because Im sure that if I nail it perfectly I can get the package into orbit on the last drop of fuel. My last flight if I pitched down a little sooner as I approached orbital velocity I may have made it.

So even after the assembly issues are figured out. Is this rocket still meant to be more difficult to fly?

[NathanKell]

The S-IVB stage already includes the instrument unit. Please post a picture of the rocket with the information panes showing, that might help.

[Motokid600]

Ive since updated to RO 8.2 and now that the gap issue on the LMA is fixed i dont have to use my improvised piece. So that plus the removal of the instiment unit and two APS modules has brought the total weight down to 597 tons. However i suspect the S-IVB is still a bit heavy despite it now having 7.4km/s of Dv. So yes.. pictures. Sorry i wouldve posted some earlier, but it took some figuin' to take a screenshot on linux.

And for what it counts. Player.log and KSP.log

But despite that heavy S-IVB i think that might do it. Im goiing to launch this right now and report back.

And success! Orbit with 807m/s left to go. Took a 265km AP, but I might have been able to fly a shallower trajectory and get more out of it. I know the actualy thing was nowhere near as stripped as mine was..

EditL Actually something just happened. When i seperated the CSM the LMA fairing panels sunk into the S-IVB and seemed to pull the CSM back in. I was able to seperate, but some some very strange behavior with those panels.

Edited March 22, 2015 by Motokid600

[stratochief66]

Hi, Motokod. I have been cleaning up some of the FASA parts of late. I am glad you have noticed and enjoyed some of the improvements, like the LMA spacing fix.

What leads you to suspect the S-IVb is overweight? Historically it looks to me like there were 2 major versions of the S-IB. I haven't been able to track down exact figures, but I believe the first stage tank was signifcantly lightened up before being used to launch 20.0 ton and 20.1 ton Skylab 2 and Skylab 3 flights. In comparison, prior to the lunar landings, what I believe to be the earlier version of the S-IB lifted the 16.5 ton Apollo 7 mission into LEO.

The S-IVb currently in RO also is a few hundred kg heavier than the one used on any S-IB as well, I believe. The reason being that the S-IB version did not include the ability to restart, which was necessary for a Saturn 5 TLI, but not for any S-IB flights.

As for the LMA behaviour, the staging of the LMA and LMA fairings is a little strange, but it might explain what you are seeing. There will be staging icons for each of the LMA fairings as well as seperating the CSM from the top attachment node of the LMA. I personally place these all in 1 stage while flying, but you would see strange behaviour if you don't. Would it be possible for you to try to capture a screenshot or two of the strange behaviour you have seen?

I am also curious if you are using the SM SPS engine to achieve orbit, or are using a partially fueled SM?

- - - Updated - - -

Also, I noticed the identical Ullage issue today as you described, Motokid600.

http://www.spaceline.org/rocketsum/saturn-v-apollo.html

The above sources suggest that solid motors were used to settle the fuel of the S-IVb during ascent, and that the ullage motors in the Saturn APS only provided ullage before TLI of the Saturn 5.

There are no solid rocket motors in FASA specifically meant to fulfill this purpose, so please use the SRM of your choosing.

I also find it rather cool the wiki page gives you the timing of launch events, as you can see the solid ullage lighting and jettison.

http://en.wikipedia.org/wiki/Saturn_IB

[Motokid600]

Hi, Motokod. I have been cleaning up some of the FASA parts of late. I am glad you have noticed and enjoyed some of the improvements, like the LMA spacing fix.

What leads you to suspect the S-IVb is overweight? Historically it looks to me like there were 2 major versions of the S-IB. I haven't been able to track down exact figures, but I believe the first stage tank was signifcantly lightened up before being used to launch 20.0 ton and 20.1 ton Skylab 2 and Skylab 3 flights. In comparison, prior to the lunar landings, what I believe to be the earlier version of the S-IB lifted the 16.5 ton Apollo 7 mission into LEO.

The S-IVb currently in RO also is a few hundred kg heavier than the one used on any S-IB as well, I believe. The reason being that the S-IB version did not include the ability to restart, which was necessary for a Saturn 5 TLI, but not for any S-IB flights.

After taking off the extra parts i had on the rocket and tweaking the fuels I was able to ge it to around those figures in the end. That and.. having just dawned on me im looking at the weight of the S-IVB with the CSM on top. >.<

As for the LMA behaviour, the staging of the LMA and LMA fairings is a little strange, but it might explain what you are seeing. There will be staging icons for each of the LMA fairings as well as seperating the CSM from the top attachment node of the LMA. I personally place these all in 1 stage while flying, but you would see strange behaviour if you don't. Would it be possible for you to try to capture a screenshot or two of the strange behaviour you have seen?

Yea i want to try and reproduce the issue in the morning and ill get some pictures. In the meantime the best i can descriube it is the panels decoubled in the wrong direction. They went in instead of out. And yea all in one stage.

I am also curious if you are using the SM SPS engine to achieve orbit, or are using a partially fueled SM?

Yes I went overkill taking weight out of the CSM.

- - - Updated - - -

Also, I noticed the identical Ullage issue today as you described, Motokid600.

http://www.spaceline.org/rocketsum/saturn-v-apollo.html

The above sources suggest that solid motors were used to settle the fuel of the S-IVb during ascent, and that the ullage motors in the Saturn APS only provided ullage before TLI of the Saturn 5.

There are no solid rocket motors in FASA specifically meant to fulfill this purpose, so please use the SRM of your choosing.

I also find it rather cool the wiki page gives you the timing of launch events, as you can see the solid ullage lighting and jettison.

http://en.wikipedia.org/wiki/Saturn_IB

Thanks for that link that helps alot. As for the ullage motors i use KW, there perfect. The issue is i cannot seem to find a 6.6m decoupler that can go under the interestage for the dual plane seperation. The larger part for the SaturnV cant be scaled. Ive had to hot stage the rocket to get ithe J2 to ignite and retro motors on the first stage so it pulls away before the interestage ( still attatched to the depleted stage ) rips off the J2. Its happened twice because i failed to put on retro motors. I am able to achieve dual plane seperation with the procedural decoupler, but its far too heavy.

Edited March 22, 2015 by Motokid600

[NathanKell]

Dual-plane separation is only between the S-IC and S-II. The S-IVB has the normal single-plane separation (interstage stays attached to the S-IB, in your case, and the S-IVB slides out).

For the panel separation issue, get all the Stock Bug Fixes from the stickied thread in Addon Releases. KSP since .24.2 has a big bug with decouplers.

[Motokid600]

No dual plane separation on the S1B? Thats werid I could've sworn I saw ullage motors on the interstage. Maybe they were pointing the other way.. Anyway I'll try that decoupler fix , thanks.

Edit: Okay. Everything I read points to the solid motors on the interstage skirt are indeed retro motors and the ullage motors were mounted on the S-IVB itself.

Edited March 22, 2015 by Motokid600

[stratochief66]

The jettison force for the LMA fairings is quite low, but they always seem to float outward slooowly when I decouple them. I only decouple them under 0 acceleration, once orbit (or for the Saturn 5, TLI) has been achieved. keep in mind, that in reality the LMA fairings were the only things holding the CSM up.

Are you decoupling the LMA upper node holding the CSM at the same time as the LMA fairings?

[Motokid600]

Sorry it took so long to get back to this. Last night I tested out the LMA fairings and they are indeed acting funny. Placed without symmetry three of the four fairings decouple normally. But it seems the first one placed onto the craft decouples in the opposite direction and moves inward. And yes the LMA node is being decoupled with the fairings. Id provide a picture, but theres not really much to see other then what i described. ( that and im having trouble taking screens in Linux. ) I also posted a log in RealFuels for another, greater issue if need be.

[MysteriousSteve]

Does someone know where to find A Vikas/Viking engine? I am trying to make a PSLV and I need it for the Second Stage.

[NathanKell]

ferram4 has just added configs for it to RO. It'll be in the next release. We need a model that looks like it, however, if anyone wants to volunteer.

[MysteriousSteve]

ferram4 has just added configs for it to RO. It'll be in the next release. We need a model that looks like it, however, if anyone wants to volunteer.

Cool! Thanks for the info Nathan.